Well ... an interesting post, indeed. I'm reading two threads to the thinking, on the one hand why we map (and what maps mean to us), and on the other hand how do we develop a style in maps.
On why I map - I read Tolkien's the Lord of the Rings when I was 11 and got hooked on the fantasy maps. Quite simple, really. I always read a lot, and the acts of imagination and virtual creation were always where I found my personal enjoyment. Little compares to the pleasure of making something new. I started making hand-drawn maps, and slowly progressed from making copies to making my own types of maps and visual language.
As for a style, the CG offers you a chance to view how a community provides for the schismogenesis of its members - their differentiation among themselves and together from members of other communities (see Bateson, an Ecology of Mind). Basically, there are two forms of difference-making process, on the one hand direct competition (symmetric schismogenesis): where, for example, CG members compete to make the best artworks they can (e.g. the competitions), and on the other hand diversification and specialization (complementary schismogenesis): where CG members focus more on the types of maps they feel they do best (e.g. city maps, hand drawn maps, etc.).
Another matter to consider is that the structure and current membership of the forum structures the work that goes on, for example the relatively heavy emphasis on fantasy maps vis "real" maps (then again, as you've noted, all maps are representations and virtual).